Rebuild and clean the carb, there is a screen in the carb that gets plugged, check the black pulse tube from the case to the carb. low speed needle 1 1/8 to 1 1/4 high speed needle 1 1/2 to 1 5/8. This is a baseline start, every motor is a little different depending on prop. If it has spark it sounds like a fuel problem.
wild bill